Segregated pressure fan



July 27, 1943. w. H. BRETZLAFF ETAL 2,325,221

SEGREGATED PRESSURE FAN Original Filed ec, 28, 19:56

- INVENTOR. M/fer Adi/0341,9 BY 6 Y P. Grimes 9.39M

ATTORNEY.

Patented July 27 1943 OFFICE sncaasa'rnn rnns s'uan FAN Walter H. Brctalaif, Detroit,

Mich; and Charles P. Grimes, Syracuse, N. Y.

Original application December 28, 1938, Serial No.

117,748. Divided and this application August 7, 1939, Serial No. 288,790

6 Claims. (01. 230,47) Our invention pertains to fans of improved efficiency and utility, and more particularly to fans comprising means for segregating the air from the different pressure areas of the fan. This application is a division of our copending patent application Serial No. 117,748 filed December 28, 1936, for Segregated pressure fan, and issued October 1'7, 1939 as Patent No. 2,176,324.

In previously known fans satisfactory operating efficiencies have not been obtained, and difficulty has been experienced because of the different air pressures set up by the fan in adjacent areas whereby the energy expanded upon the air by the fan was largely dissipated in churning the air and causing currents of air to flow in and out of the path of the fan. More particularly such difficulties have been very serious when projecting the air thru a conduit to a remote location from the fan, and previously when fans have been utilized with conduits, low efficiency and unsatisfactory operating characteristics 'have resulted. Also, it has previously been necessary to provide individual fans to supply air separately to difierent locations for different pressure and velocity conditions.

It is an object of our invention to provide a fan of improved efficiency.

It is also an object of our invention to provide a fan comprising means for segregating the air projected from the different pressure areas of the fan whereby separated air streams may be supplied to separate points for use under different pressure and velocity conditions.

It is also a further object of our invention to provide a segregated pressure air source comprising a combination of an air impeller, and an air collecting plenum chamber properly disposed in a high pressure portion of the air stream for receiving and segregating the air projected from the adjacent portion of the impeller whereb it may be passed through an associated conduit for supplying air under higher pressure or higher velocity conditions, and the air projected from the other portions of the fan may be utilized at a difierent location under diii'erent velocity and air conditions.

A further object of our invention is to provide the combination of a centrifugal type of fan with a pressure plenum chamber of annular conformation surrounding the outer extremities of the fan and comprising an open air receiving port extending around the inside portion of the plenum chamber and so disposed relative to the fan that the high pressure air is received therefrom and additional conduit means inclosing the low pressure air therefrom in segregated relation.

vantages thereof will best be understood from the following description, when read in connection with the accompanying drawing,.in which:

Fig; 1 is a plan view partially sectioned and broken away showing an embodiment of our invention comprising a combined centrifugal type and propeller type of fan;

Fig. 2 is a cros sectional view on line 2-2 thereof and Fig. 3 is an enlarged sectional view taken on line 3-3 of Fig. 1. Referring more specifically to Figs. 1 and 2 of the drawing, we have illustratively disclosed our segregated air pressure source, comprising a special composite type of fan. Such a fan i conveniently constructed from a dished sheet metal member 10, having cylindrical or conical side walls, and from which portions of the closed end wall are displaced to provide the radially extended propeller blades 13 which may be thereafter twisted to proper angular positions and suitably curved. By suitably slitting the conical or cylindrical side walls of the fan dish 10, blades ll may be turned to providecentrii'ugal or turbine blades, as will be readily understood. A circumferential rim 14 is left uncut for connecting between the outer ends of the propeller blades 13 and the lower ends of the turbine blades II. The outer or open edge 11 of the sheet metal fan disc 10 are preferably turned outwardly around a reinforcing rod 19 whereby astifl! reinforced rim is provided. At their innermost ends the propeller type blades 13 are secured as by rivets 8| for rigid connection to flange 83 upon a hub 85. The hub 85 is suitably apertured for axial mounting upon the extended shaft 88 of a suitable motor 81 by which the fan is'driven.

Surrounding and enclosing the centrifugal blades II of the cylindrical fan, we provide a scroll chamber 83 enclosed by walls 8| for receiving the air projected therefrom, and converting the velocity head thereof into a suitable pressure head. The scroll diverges from the fan in the direction of rotation at an angle of divergence which is preferably about 12 degrees, in accordance with the usual practice.

In practice we have found that fans of the centrifugal type also project the air into different pressure areas spaced axially along the outer edges of the fan blades, similarly to propeller types of fans which are discussed in greater detail in our copending patent application Serial No.'117,748. In accordance with the principle of our invention, a pressure plenum chamber 93 is provided which is enclosed by suitable spaced annular side walls 95, which pass through an intermediate portion of the scroll chamber. The side walls 95 are joined by an external wall 91 and the air collector chamber opens inwardly adjacent the fan blades II. The side walls 95 of the plenum chamber 99 are suitably spaced to provide an open air receiving port adjacent the outer tips of the fan elements I I of a proper dimension for receiving and segregating the higher pressure air therefrom.

The outer peripheral wall 91 of the plenum chamber is also of angularly diverging conformation to define a scroll for receiving the high pressure air, which is thus converted from a velocity head to a pressure head. The inwardly directed edges of the plenum side walls 95 are tapered to provide sharp edged fins 96 offering minimum resistance to the air stream. The scroll chambers 89 and 93 may start from different circumferential points around the fan and may be made with different angles of divergence as desired.

Connecting from the scroll chamber 89, a conduit 99 is provided which leads tangentially therefrom for leading ofl the trapped air. As shown in Fig. 2, the cross section of the scroll chamber 89 is radially elongated or extended at the point where the conduit 99 connects, and the conduit is preferably suitably tapered to provide a proper cross section for connection with the standard conduits generally used in accordance with the usual practice in the ventilating and air conditioning arts. For leading the higher pressure at I03 extend in spaced relation from the side wall of the scroll chamber 99, and from each of the bracket arms I03 a motor supporting arm I05 projects radially toward the axis of the fan. For supporting the shell of the motor, fingers I01 of suitable curvature are provided on the inner ends of the arms I05. For holding the other end of the motor shell, it is nested in a socket I I I in a spider I09. The spider has a cushion bed II3 for the end of the motor and radially extending armsI I 4, which are secured by bolts I I5 to the outer ends of the brackets I03. The fan is thus supported in cushioned relation from the frame and housing of the air impelling unit. A flange III extends axially from the inlet end of the fan scroll 9I for receiving a sleeve II9 which holds a shell I2I. The shell I2I contains any open member or filter or other air-treating material I23 through which it is desired to draw the air.

In operation the blades 13 of the propeller fan draw air in through the shell I2 I' and discharge a large volume for use adjacent the fan unit. Simultaneously, the centrifugal fan is also drawing air through the filter, and by a combination of fan forces, is throwing it through its blades 'II in a generally radial and tangential direction across most of the blade'width.

By searching with the impact tube, as more fully described and shown in our copending application Serial No. 117,748, issued on October 17, 1939, as Patent No. 2,176,324 the'various areas of segregated pressures are found and recorded. The annular region of pressures desired is then housed over by a suitable scroll that may extend over a complete circumference, or any portion desired, and for one or more take oifs. In this manner high pressure high velocity air is efllciently trapped from the high velocity portion of the air stream into one or more smooth annular plenum chambers where both its velocity head and pressure head are available for remote application, while at the same time a large volume of air is delivered through the large central discharge area for local use. The separation of the differ-- ent portions of the air stream thrown from the high velocity portions of the fan elements, with different velocities and pressures, tends to eliminate interaction between these different air currents and this also tends to improve the operating efliciency of the unit for delivering high pressure high velocity air and for delivering air from a single unit for use under different conditions of pressure and velocity. 7

Aside from the specific embodiments of the invention here described, it will be understood that numerous details of the construction may be altered or omitted without departing from the scope of the invention as disclosed and claimed, and that we do not desire to limit the invention to the exact constructions herein set forth.

We claim:

1. In a segregated pressure airimpeller the combination of, a dished member of sheet metal, centrifugal air throwing blades distorted from a peripheral wall of said member, propeller type blades distorted from a portion of said member for projecting air axially, means for rotatably supporting said member, and means for receiving the air from the centrifugal blades in segregated relation from the air thrown axiall from the propeller blades.

2. In a segregated pressure air impeller unit the combination of, a common entry chamber, a rotatable fan having a hub, disc type propeller blades extending radially therefrom to project air axially therethrough, centrifugal blades disposed at periphery of propeller blades and associated therewith to draw air from said common entry chamber and project air outwardly in the plane of rotation, motive means for operating said fan, an air collecting scroll chamber surrounding the outer extremities of said centrifugal blades with an air receiving port adjacent said blades and disposed in the high pressure portion of the centrifugally thrown air stream for separately collecting said high pressure portion of discharged air for separate use, and a. chamber for similarly collecting air from other portions of the centrifugally projected air stream in segregated relation from the high pressure air and the axially projected air as projected by the disc type propeller blades.

3. In a segregated pressure air impeller unit the combination of, a common entry chamber, a rotatable fan having a hub, disc type propeller blades extending radially therefrom to project air axially therethrough, centrifugal blades disposed at the periphery of the propeller blades and associated therewith to draw air from said common entry chamber and project air outwardly in the plane of rotation, motive means for operating said fan, an air collecting scroll chamber surrounding the outer extremities of said centrifugal blades with an air receiving port adjacent said blades, and disposed in the high pressure portion of the centrifugally thrown air stream for separately collecting said high pressure portion of discharged air for separate use,

a chamber for similarly collecting air from other portions of the centrifugally projected air stream in segregated relation from the high pressure air and the axially projected air as projected by the disc type propeller blades, and outlet conduits opening from said chambers substantially tangentially for leading collected air therefrom in its direction of rotation as it is thrown from the fan to utilize both the pressure and the velocity heads of the collected air.

4. In a segregated pressure air impeller unit the combination of, a rotatable fan having a set of centrifugal air projecting blades disposed for projecting air peripherally, said fan having a set of disc type propeller blades disposed for projecting air axially, a common entry chamber for supplying air axially for both sets of blades, an air collecting scroll chamber surrounding the outer extremities of said centrifugal air deflecting blades and disposed in the high pressure portion of the air stream, an open air receiving port in the inner side of said scroll chamber for receiving the air projected peripherally from the air projecting blades, and a chamber for receiving air from other portions of the air stream pro- Jected from said blades in segregated relation.

5. In combination in a segregated pressure air I impeller unit, a fan having propeller blades projecting outwardly from the center of rotation for moving a central stream of low velocity air substantially. anally, means for rotatably supporting said Ian, separate auxiliary centrifugal air throwing means adjacent to and connected with said propeller blades for drawing air from the low velocity central air stream and throwing a high velocity stream of air radially, and means defining an air receiving enclosure of substantially annular conformation disposed around and closely coupled to the periphery of said centrifugal air throwing means for efiectively segregating 'the radially thrown air from the axially thrown air to collect a maximum volume of high pres- .sure air in said enclosure for supplying said air for any desired use separately from the axially thrown air.

6. In a segregated pressure air impeller the combination of, a rotatable fan, propeller type blades on said fan for moving a stream of air axially for central delivery, supplemental radial blade means on said fan additional to the propeller type blades for diverting air from the axial moving air stream and for projecting the diverted air radially, an air inlet chamber for admitting air to all portions of the intake side of fan, an air treating member in said air inlet chamber having air flow resistance which causes the air to linger on the fan accentuating the radial air throwing characteristics of the fan, and means for delivering the radially projected air separately from the centrally delivered portion of the axially moving air stream.

WALTER H. BRE'I'ZLAFF. CHARLES P. GRIMES. 

